I think Ocaml's learnability is a huge asset. I'm surely biased, my main skillset is in Python so of course the low friction to a new language is more important to me rather than say, a Haskell user, or a Scala user. The 2nd edition of Real World Ocaml on Yaron Minsky's site is a great resource for me, though once multicore is actually stable and fully activated there will be still more learning to do.
It's a really nice change to embrace types so close to the top of the software process. Things like Mypy have been a godsend, and I've said in the past that Mypyc represents the biggest quantum leap that Python will ever make, but having such a mature and FAST compiler, with a syntax that's clean and consistent on top of a huge, mature ecosystem (not as huge as pypi, ofc) is just such a powerful value proposition.
Aside from Multicore, I think OWL (ocaml.xyz) is a big leap forward for the ecosystem too. I can see some finance shops putting together Ocaml-Jupyter notebooks and that sort of thing. Maybe bio-tech researchers with FP backgrounds could get more into it.
This is all just my opinion, but having leaned pretty heavy on Python's ecosystem for a pretty long period of time, I am VERY optimistic about finding ways to replace things with Ocaml for speed and correctness. I do enjoy Python, but I think the typed-Python renaissance is about 3 years too late now. It'll win more battles in the years to come, but I see war on the horizon, and not just with Ocaml either.